For the production of molded objects with a hollow space, sand cores and salt cores are used in casting technology, and the cores are dissolved after casting to form the hollow space in the cast body. Both sand cores and molded salt cores, however, have a low mechanical strength. They are thus difficult to handle. Because of their low strength, in practice they are usable only in casting technology for producing molded objects, but not in other processes for producing molded objects.
It is further known to use cores of electrically conducting wax in the production of molded objects with hollow spaces by electrolytic deposition, and the wax is then melted out. The disadvantage of this process, among others, is that one is limited, in the selection of materials, to metals that are suitable for electrolytical deposition.